dmapool: simplify freeing

The actions for busy and not busy are mostly the same, so combine these
and remove the unnecessary function.  Also, the pool is about to be freed
so there's no need to poison the page data since we only check for poison
on alloc, which can't be done on a freed pool.

Link: https://lkml.kernel.org/r/20230126215125.4069751-10-kbusch@meta.com
Fixes: 2d55c16c0c54 ("dmapool: create/destroy cleanup")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/dmapool.c b/mm/dmapool.c
index 9e98065..4dea2a0 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -312,16 +312,6 @@
 	return page->in_use != 0;
 }
 
-static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
-{
-	dma_addr_t dma = page->dma;
-
-	pool_init_page(pool, page);
-	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
-	list_del(&page->page_list);
-	kfree(page);
-}
-
 /**
  * dma_pool_destroy - destroys a pool of dma memory blocks.
  * @pool: dma pool that will be destroyed
@@ -349,14 +339,14 @@
 	mutex_unlock(&pools_reg_lock);
 
 	list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
-		if (is_page_busy(page)) {
+		if (!is_page_busy(page))
+			dma_free_coherent(pool->dev, pool->allocation,
+					  page->vaddr, page->dma);
+		else
 			dev_err(pool->dev, "%s %s, %p busy\n", __func__,
 				pool->name, page->vaddr);
-			/* leak the still-in-use consistent memory */
-			list_del(&page->page_list);
-			kfree(page);
-		} else
-			pool_free_page(pool, page);
+		list_del(&page->page_list);
+		kfree(page);
 	}
 
 	kfree(pool);